Panels, such as those of sheet metal, are used to manufacture a variety of structures. By way of example, portions of vehicle bodies, such as, for example, hoods and doors, are often fabricated from panels of sheet metal, which may be provided with a variety of shapes, such as, for example, via stamping.
Often times a pair of such panels are joined together via a hemming procedure. A typical hemming procedure utilizes an outer panel and an inner panel. Typically, the outer panel is provided with a border flange, which is folded over or hemmed over the inner panel during the hemming procedure. For example, in the case of a vehicle hood, an inner panel may be centered on an outer panel and border flanges on four peripheral sides of the outer panel may be hemmed over the inner panel.
In addition to the hemming procedure, a liquid adhesive is often times utilized to bond the inner and outer panels together. The adhesive is typically applied to the outer panel prior to the hemming procedure. After the adhesive is applied, the outer and inner panels are pressed together, which causes the adhesive to flow both away and toward the border flange. After the adhesive is applied and the panels are pressed together, the flange ends on the outer panel are hemmed over the edges of the inner panel. Depending on the type of adhesive utilized, a heating process may be employed so that the adhesive solidifies and cures to securely bond the inner and outer panels together.
It is desirable to reduce the amount of adhesive used to bond the inner and outer panels together. Yet, it is often times difficult to select a suitable adhesive with the proper amount of viscosity and expansion rate to ensure adequate bonding of the inner panel to the hemmed portion to the outer panel.
Depending on the application, it may also be desirable in some situations for the space between the inner panel and the hemmed portion on the outer panel to be substantially filled with adhesive. Not only does such an arrangement strengthen the bond between the inner and outer panels, since it increases the surface area bonding the inner and outer panels, but it also prevents contaminants, such as moisture from entering the hemmed portion. Entry of moisture and other contaminants into the hemmed portion may cause or contribute to corrosion of the hemmed portion as well as the edge of the inner panel, and thus weaken the joint between the inner and outer panels. Even in applications where it is desirable to seal and substantially fill the hemmed portion, selecting a suitable adhesive with the proper amount of viscosity and expansion rate has been difficult.
The present invention is directed at an improved hemmed panel.